1 tablespoon olive or vegetable oil
2 large carrots, peeled and diced
4 whole stalks celery, diced
1 medium yellow onion, diced
1/2 teaspoon oregano
1/2 teaspoon salt
1 quart low-sodium chicken broth (store-bought or homemade)
1 cup water
1 cup pearled or quick-cooking barley
2 cups diced, cooked chicken
1 to 2 tablespoons fresh lemon juice, to taste
Parsley, to garnish
Heat the oil in a medium (3- to 5-quart) Dutch oven or heavy-bottomed soup pot. Add the carrots, celery, onion, oregano, and salt. Stir to coat the vegetables with the oil, then cover the pot and let the vegetables sweat until the onions are translucent and carrots are softened, about 10 minutes. No need to stir while the vegetables are sweating.
Add the chicken broth, water, and barley to the pot. Bring up to a simmer, then cover and turn down to low. Let simmer until the barley is cooked through, 10 to 30 minutes depending on the variety you’ve used.
Uncover the pot and add the cooked chicken. Allow to warm through, about 2 minutes, then add 1 tablespoon of lemon juice. Taste and add more lemon juice, salt, or pepper to taste. Serve right away, garnished with parsley if desired.